What the FDA labels say about taking them together
Nefazodone and trastuzumab emtansine
Trastuzumab emtansine's FDA label of April 1, 2026 names nefazodone in its drug interactions section; the nefazodone label PlainMeds reads does not name trastuzumab emtansine. The trastuzumab emtansine label: “Concomitant use of strong CYP3A4 inhibitors with KADCYLA should be avoided due to the potential for an increase in DM1 exposure and toxicity.”
Check it at the source: the nefazodone FDA label on DailyMed (effective July 31, 2025, Teva Pharmaceuticals USA, Inc.); the trastuzumab emtansine FDA label on DailyMed (effective April 1, 2026).
What does the nefazodone label say about trastuzumab emtansine?
Nefazodone's label (effective July 31, 2025) does not name trastuzumab emtansine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Nefazodone Hydrochloride), Teva Pharmaceuticals USA, Inc., effective July 31, 2025 (SPL set 51ff7db5-aaf9-4c3c-86e6-958ebf16b60f), via openFDA; the full label on DailyMed
What does the trastuzumab emtansine label say about nefazodone?
Trastuzumab emtansine label, drug interactionsConcomitant use of strong CYP3A4 inhibitors (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, and voriconazole) with KADCYLA should be avoided due to the potential for an increase in DM1 exposure and toxicity.
Source: FDA drug label (KADCYLA), Genentech, Inc., effective April 1, 2026 (SPL set 23f3c1f4-0fc8-4804-a9e3-04cf25dd302e), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Nefazodone | Trastuzumab emtansine | |
|---|---|---|
| Labeled for | Depression | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $1.17 per tablet 100 mg tablet | n/a |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once